1) Field of the Invention
The subject invention generally relates to a filter assembly and method of filtering utilizing the filter assembly to filter a fluid. More specifically, the subject invention relates to an adjustable filter assembly including a filter element and filtration apertures that are defined between crests and troughs of adjacent wave coils of the filter element wherein the filtration apertures are adjustable.
2) Description of Related Art
Spring filters are known in the art. Helically- or spirally-wound spring filters are also known in the art. Examples of such conventional spring filters are disclosed in U.S. Pat. Nos. 4,113,000; 4,199,454; and 5,152,892. Conventional spring filters, including the helically- and spirally-wound spring filters disclosed in the above-referenced patents, are deficient for various reasons. For instance, certain conventional spring filters are not adjustable. Other conventional spring filters are not easily adjustable and are not easily manufactured. As one specific example, the conventional spring filter disclosed in the '892 patent is deficient because the entire coil of this conventional spring filter, which is made up of a plurality of individual flat coils, is extremely weak having a k factor of about zero. As a result, filtration gaps, or filtration apertures, can not be maintained between the individual flat coils when the spring filter is vertically-oriented. This conventional spring filter is also particularly difficult to manufacture. More specifically, this conventional spring filter requires that the individual flat coils of the filter be manufactured such that the filtration apertures, between adjacent flat coils progressively increase in size and pitch which, as understood by those skilled in the art, is a particularly cumbersome requirement. This conventional spring filter further requires that projections be machined into each coil to maintain a minimum filtration aperture between adjacent coils of the filter, thus involving additional machining requirements and even limits on size of the spring filter.
Due to the deficiencies identified in the spring filters of the prior art, including those set forth above, it is desirable to implement an adjustable filter assembly that is ideal to manufacture and that uniquely defines a filtration aperture between adjacent coils of a filter element for optimum filtering of fluids due to the adjustability of the filtration aperture. It is also desirable that the adjustable filter assembly according to the subject invention can be easily manufactured into a wide range of sizes and stiffnesses of the filter element.